20200830

xiaoyong931011

2020-08-30 4f95e1fddf7468af9bc7d5409f7e2b80d5325182

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package com.xcong.excoin.common.utils; 
import org.springframework.beans.BeansException; 
import org.springframework.beans.factory.DisposableBean; 
import org.springframework.context.ApplicationContext; 
import org.springframework.context.ApplicationContextAware; 
import org.springframework.stereotype.Component; 
 
import lombok.extern.slf4j.Slf4j; 
@Component 
@Slf4j 
public class SpringContextHolder implements ApplicationContextAware, DisposableBean { 
 
    private static ApplicationContext applicationContext = null; 
 
    /** 
     * 从静态变量applicationContext中取得Bean, 自动转型为所赋值对象的类型. 
     */ 
    @SuppressWarnings("unchecked") 
    public static <T> T getBean(String name) { 
        assertContextInjected(); 
        return (T) applicationContext.getBean(name); 
    } 
 
    /** 
     * 从静态变量applicationContext中取得Bean, 自动转型为所赋值对象的类型. 
     */ 
    public static <T> T getBean(Class<T> requiredType) { 
        assertContextInjected(); 
        return applicationContext.getBean(requiredType); 
    } 
 
    private static void assertContextInjected() { 
        if (applicationContext == null) { 
            throw new IllegalStateException("applicaitonContext属性未注入, 请在applicationContext" + 
                    ".xml中定义SpringContextHolder或在SpringBoot启动类中注册SpringContextHolder."); 
        } 
    } 
 
    /** 
     * 检查ApplicationContext不为空. 
     */ 
    private static void clearHolder() { 
        log.debug("清除SpringContextHolder中的ApplicationContext:" + applicationContext); 
        applicationContext = null; 
    } 
 
    @Override 
    public void destroy() throws Exception { 
        SpringContextHolder.clearHolder(); 
    } 
 
    @Override 
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException { 
        if (SpringContextHolder.applicationContext != null) { 
            log.warn("SpringContextHolder中的ApplicationContext被覆盖, 原有ApplicationContext为:" + SpringContextHolder.applicationContext); 
        } 
        SpringContextHolder.applicationContext = applicationContext; 
    } 
}